Effect of Organic Amendments on the Water Stress Resistance of Corn Varieties during Vegetative Stage in Ultisols

Background: Water stress is one of the most crucial limiting factors in maize production on Ultisols. One solution that could be adopted to solve this problem is applying organic soil amendment. Methods: This study evaluated three varieties of corn: NK-Jumbo, Srikandi Kuning and Lamuru. The water stress treatment consists of 75% field capacity (without water stress) and 37.5% field capacity (water stress treatment). The organic amendment consists of without soil amendment, rice-straw 10 tons ha-1, biochar 10 tons ha-1 and rice straw 5 tons ha-1 + biochar 5 tons ha-1. A factorial, completely randomized design was used in this research. Result: Water stress and organic amendments affect total stomata, leaf curl, leaf area, proline content, shoot and root dry weight, shoot-root ratio and biomass production of corn. Applying organic amendments increases corn’s resistance to water stress, indicated by decreased plant proline content and increased biomass. The proline content of corn by application of organic amendment with rice straw 5 tons ha-1 + biochar 5 tons ha-1 (70.41 µ mol/g) was lower than the proline content of treatment without amendments (93.69 µ mol/g). NK-Jumbo was the most resistant variety to water stress conditions.